Sine and cosine function voltage device



May 16, 1950 G. A. CROWTHER 2,507,890

SINE AND COSINE FUNCTION VOLTAGE DEVICE Filed Nov. 19, 1947 '5Sheets-Sheet 1 INVENTOR GEORGE A. Ceowrugk May 16, 1950 Filed NOV. 19,1947 G. A. CROWTHER SINE AND COSINE FUNCTION VOLTAGE DEVICE 3Sheets-Sheet 2 INVENTOR GEORGE A.CROWTHR jian/$ HIS ATTORNEY y 1950 G.A. CROWTHER 2,507,890

SINE AND COSINE FUNCTION VOLTAGE DEVICE Filed NOV. 19, 1947 5Sheets-Sheet 5 31 9' 3 2,5 ong/cg'v ||I v a a 41 34 H 52 :8:- 4' s K 1sIIIIIllllIIIIIIIIIIIIIIIII||lllllll[IlllllllllllllllllllllllllllllllllflllllllllllllllllllllllIIIIHIHHIIIIIIIIIIIIIINVENTOR GEORGE A.CROPW'HER HIS ATTORNEY Patented May 16, 1950 SINE ANDCOSINE FUNCTION VOLTAGE DEVICE George A. Crowther, Manhasset, N. Y.,assignor to The Sperry Corporation, a corporation of Delaware 'Application November 19, 1947, Serial No. 786,998

.5 Claims. I

This invention relates to a device for producing voltages which areproportional to selected functions of an angle and more particularly toa mechanically operated device for deriving voltages which are functionsof the sine and co-sine, respectively, of the angle which is set intothe device.

An object of the invention is to provide an accurate and dependabledevice of the type above indicated.

Various other objects and advantages will be "apparent as the nature ofthe invention is more fully disclosed.

The present invention is based on the fact that the hypocycloid tracedby a point on the periphery of the inner gear of an epicyclic trainrotating around the inner periphery of an outer gear which is twice thediameter of the inner gear is a-straight line extending along thediameter of the outer gear. I accordingly provide a linear resistancewhich extends along the diameter of the outer gear along which a contactcarried by an arm on the inner gear advances. The relationship is suchthat the distance between the contact and the center of the resistancerepresents either the sine or the co-sine of the angular position of theinternal gear. If a voltage drop is impressed across the resistance, thevoltage between the point of contact and the center of the resistancerepresents the corresponding angular function.

Although the novel features which are characteristic of this inventionare pointed out more in which a specific embodiment thereof has been setforth'for purpose of illustration. In the drawings: Fig. 1 is a top planview of a device embodying the present invention;

P Fig. 2 is a section taken on the line 2-2 of Fig. 1;

Fig. 3 is a bottom plan view of the device with the internal gear in adifferent position; Fig. 4 is a side elevation of the device;

Fig; 5 is'a partial detail sectional view on an enlarged scale takenalong the line 5-5 of Fig. 3; Fig. 6 is a partial detail sectional viewon an enlarged scale taken along the line 8-6 of Fig. 1 Fig. '7 is adetail view on an enlarged scale of a contact arm; and

Fig. 8 is a schematic wiring diagram. Referring to the drawings more indetail. the device is shown as comprising a stationary ring outer gearof the epicyclic train. Extendingdiametrically across this ring In onopposite sides 10' having internal gear teeth H which form the 55thereof and arranged at right angles to each other are a, pair of rodsI2 and I3, respectively, carrying wound resistance windings l4 and I5and a pair of contact strips l8 and I9, respectively, havinglongitudinal slots therein for the purpose to be described. The contactstrip [8 and rod I2 are supported by insulated bushings 2|] which aresecured to the ring ID by screws 2| (Fig. 2). The rod l3 and contactstrip l9 are secured to the other side of the ring 10 by insulatedbushings 22 (Fi 4).

A disc is mounted concentric with the ring l0 and is provided withexternal gear teeth 3| and peripheral shoulders 32. The disc 30 isrotatably mounted in spools 34 having annular flanges 35 engaging theshoulders 32 and forming a channel 36 therebetween to receive theexternal teeth 3! of the disc 30. The spools 34, as shown in Fig. 5, aremounted on ball bearings on studs 31 attached to the ring [0.

The disc 30 is driven by a pinion 40 (Figs. 1 and 6) secured by a nut toan input shaft 4| journalled in ball bearings 43 mounted in a bushing 42and the ring Hi. The shaft 4| constitutes an input by means of which theangle whose functions are to be measured is fed into the disc 30.

An epicyclic gear which is one-half of the diameter of the innerperiphery of the ring I0 is provided with external teeth 49 engaging theinternal teeth H of the gear I!) and is mounted in alignment therewithby means of a plurality of spools 5| which are journalled on studs 52carried by the gear 50 and are formed with flanges 53 which span theinternal flange 54 of an opening 55 in the disc 30. The gear 50 is freeto rotate within the disc 30 as the spools 5| rotate around the innerperiphery of the opening 55.

The gear 50 is provided with a central opening in which an insulatingdisc 6|] and an insulating cup 61 are secured. The disc 60, as shown indetail in Fig. 7, carries a spring arm 62 which engages the contactstrip 18 and a spring arm 63 carrying a contact pin 64 extending throughan aperture 65 in the arm 62 and through the longitudinal slot 61 in thestrip l'8 to engage the winding I4 on the bar l2. The arms 52 and 53 areheld in electrical contact by screws 56 by means of which they aresecured to the disc and provide an electrical contact between thecontact strip l8 and the point of contact of the pin 64 with the windingI4. Similar arms Hi and H are carried by the cup BI. The arm ll! engagesthe contact strip is and the arm H carries a pin 12 extending through anaperture '14 in the arm 10 and through the longitudinal slot 13 in thestrip l9 to engage responding angle.

this figure the primary 80 of a transformer BI is.

connected to an A. C. line 82 and the secondary 83 thereof is connectedto leads 84 and 85. For.

maintaining the voltage on the leads B4 and 85 equal and opposite withrespect to ground, a

resistor 86 is connected across theseleads and a center tap 37 isgrounded as at 88. The line 84 is connected to leads 90 and 91 which arecon.- nected to one side of the resistance windings l4 and I5,respectively. The lead 85 is connected to leads 92 and 93 which areconnected to the otheriside of the resistance windings l4. and'l5. A;lead-9:3 is connected to the contact strip I8 and .a lead 95 isconnected to the. contact strip 9.

The purpose of the center ground connection 88 is to maintain thecenters oithe windings 14 and 15 at ground potential Withoutrequiring alead to'these windings themselves. Obviously if the center. of thesecondary. 83 is grounded the resistor 8.6.could be omitted. Also, if aD. C. voltage is tobe measured the transformer, secondary 83 may bereplaced by a battery or other D. C. source, the center of which isgrounded so asto maintain the leads .84.and 8.5 atopposite potentials.

In the operation-oi this device the angle whose function isv to bemeasured is set into the shaft 41 and, throughthe gear 40-and theexternalgear on the disc as, drives the disc as through a cor- Therotation of the disc 30 causes the internal-epicyclic gear 56 toroll-around the inside of the ring in and, as pointed out above, causesthe pins 54 and 12 to move in straight lines across the correspondingresist- :ance windings i4 and Hi. In the position shown in Figs. 1' and2, the axis of the gear 50 lies directly under the resistor i l. In.thisposition the pin 64 is in contact with the extreme endofthe resistancewinding l iand the pin '12; is in contact with'the center oftheresistance winding-l5. As-

suming this to be the zero angle position, the voltagedrop between thepin [Ni and the center of the winding I4 represents the co-sine of theangle'which in this-case isunity, and the voltage drop between the pin12 and the center of the winding 53. representsthe sine of the angle.which in this case is zero. If the disc '3fi' is. driven to the positionshown in Figs. 3 and 4, the axis of the gear as is advanced around thering. H] byan angle a and the pins 54 and 12 are shifted along thewindings It and IE to positions the distance from which to therespective centers correspond to the co-sine and sine of'the angle (1.Hence the voltage between the leads 9.5. and 94 andground areproportionalto the sine and cosine; respectively, of the angles.

It; will be noted that these voltages vary from zero at the center ,ofthe respective windings M and l5v in a plus or minus direction,depending upon whether the disc Si} is shifted in a clockwise orcounterclockwise direction. Hence the sign of the voltage indicates thedirection of movement of the disc as and the value of the voltagerepresents the sine and co-sine of the actual angle of movement. Thevoltages may of course be used in electrical computing apparatus forvarious. purposes.

Although a specific embodiment of the invention is shown for purposes ofillustration, it is to be understood that various changes andadaptations may be made therein as will be readily apparent to a personskilled in the art and that the invention may be applied to varioususes. The scope of the invention is only to be restricted in accordancewith the following claims.

What is claimed is:

1. An apparatus for deriving a voltage which representsafunction ofeither the sine or cosine ofv an angle, comprising an outer ring memherand an inner disc member connected to rotate around..-th e,innerperiphery thereof as an epicyclic train, said inner member having adiameter onehalf the internal diameter of said ring member, a linearresistance carrying a current extending diametrically across said ringmember, a contact carried at the periphery of said inner member adaptedto advance linearly along said resistance due to the rotation of saidmembers, and electrical connections to said resistance and to saidcontact to derive from said resistance a voltage, representing thelinear distance of said contact from the center of said resistance.

2. Anapparatus iorderiving a voltagewhich represents a .iunction ol thesine and co-sineof an angle, comprising a stationary ring member havinginternal gear teeth, a disc mounted concentric therewith, means rotatingsaid disc through-an angle representing the angle to be measured, anepicyclic gear member rotatably mounted on said disc and engagingtheinternal teeth of saidring member and having a diameter equal toone-half the diameter of said ring member, alinear resistance carrying acurrent mounted on eachside of said ring member and extendingdiametrically 'thereacross, the two resistances beingdisposed at rightangles toeach other,.col 1- tacts carried by said epicyclic gear indiametrical- 1y opposite positions and adapted to engage the respectiveresistances, and electrical connections to said resistances and to saidcontacts for deriving from the resistances voltages proportional tothe.- displacement of said contacts from. the center of the respectiveresistances.

3. A. device as set forth in claim 2 in which stationary contact stripsare mounted adjacent saidresistances and said contacts are arranged to,make contact between said strips and said resistances, whereby saidcontact strips provide electrical connections to said contacts.

4; An apparatus as set forth in claim 3 in which said contacts eachcomprise a pair of spring arms adapted to. make contact, respectively,withsaid strips and with said resistances.

5.. An-apparatus as set forth in claim 4 in which electrical connectionsare made to the two ends of said resistances and to said contact'stripsand equal and opposite voltages are appliedto the two ends of saidresistances.

GEORGE A. CROWTHER.

REFERENCES, CITED The following references are of record in the fileofthis patent:

UNITED STATES. PATENTS Number Name Date 1,940,102 Roberton Dec. 19, 19332,080,186 Reymond May 11, 1937 2,416,363 Wellings Feb. 25, 1947

